Shaft-sealing system



July 9, 1968 P. F. DONLEY SHAFTSEALING SYSTEM Filed Oct. 16, 1963 32 2a5 594 2 6 w 35 4 INVENTOR.

ATTOQA/E/S United States Patent 3,391,941 SHAFT-SEALING SYSTEM Philip F.Donley, Shaker Heights, Ohio, assignor to Donley Products, Inc.,Clevetand, Ohio, a corporation of Ohio Filed Get. 16, 1963, Ser. No.316,617 3 Claims. (Cl. 277-63) This invention r-erates to ashaft-sealing s stem, particularly a shaft-sealing system for a pump orother machine characterized by a housing, a shaft extending through oneof the walls of the housing, a rotatable member carried by the shaft,and a stationary member spaced from the rotatable member.

For convenience, the invention will be described as applied to pumps ofthe impeller type. Pumps of this kind are often used under conditions inwhich the pumpage takes the form of a liquid such as petroleum which,because of the presence of grit, is hard on the sealing systern.However, grit is not always to be found in pump-age;

for instance, the pumpage may take the form of a clear liquid such as apetroleum distillate, carbon tetrachloride, carbon bi-sulphide, anindustrial alcohol or the like. All of the latter and a good many otherliquids commonly moved by impeller pumps can be troublesome for variousreasons; viz., a. tendency to corrode metal, a tendency to leak pastsealing surfaces, a tendency to develop escape routes by-passin thesealing surfaces, etc. In many cases, moreover, it is important topreclude contamination of the pumpage by shaft lubricants that may tendto work their way into the pumpage by capillary action. These andsimilar factors have heretofore made almost impossibly ditlicult demandson a great many conventional shaft-sealing systems, particularly thoseemploying mechanical sealing units.

However, in the recent past highly efficient mechanical sealing unitshave reached the commercial market, illustrative examples being thefloating sealing units shown and described in US. Patent 3,028,163 to A.H. Heinrich and in the pending patent application of Philip F. Donleyidentified as Ser. No. 180,612 (now US. Patent No. 3,218,086). Efficientthough they are, such sealing units do not provide the whole answer tothe problem for the reason that they constitute only a part of thesealing system as a whole. Thus their performance can be and isinfluenced by such factors as the design, construction and compositionof the seating elements and/or the manner of their incorporation in theorgan zation. For example, a seating element of metal that has beeninaccurately machined, a seating element of carbon that has beenmechanically distorted, or a seating element of any kind that is notproperly installed will provide an environment that can prevent even ahighly efficient sealing unit from delivering maximum performance.

One of the principal objects of the present invention is to provideimproved sealing systems in which the seating element or elements cancooperate with the sealing unit in such manner as to make it possible totake better advantage of the potentialities of the latter.

Gther objects, advantages and features of the invention will be apparentfrom the description which follows and from the accompanying drawings,in which:

FIGURE 1 is a fragmentary section with parts in elevation through a pumpincorporating an improved sealing system within the purview of thepresent invention.

FIGURES 2 and 3 are enlarged central sections through sub-assemblieswhich in FIGURE 1 flank the sealing unit on its left and right'handsides, respectively.

FIGURE 4 is an exploded view of the components going to make up thesub-assembly shown in FIGURE 3.

FIGURE 5 is a central section through a modified form of seating elementprovided with an oversize stay ring.

3,391,941 Patented July 9, 1968 In FIGURE 1 is shown a portion of a pumpof the impeller type one of the walls of which has a cylindricalextension 1a provided with a longitudinally extending opening of thenature of a chamber for the reception of the several componentsdescribed hereinafter. Impeller 2, which comprises and may be describedas a rotatable end ember, is held in place at the inboard end of theextension In by a tapped nut 3 that normally seats against the hub 2a ofimpeller 2. Nut 3 cooperates with and is screwed into place on thethreaded portion 4a of the reduced end 4 of pump shaft 5.

"At the outboard end of extension 1a is a stationary end member 6 of thenature of a clamping ring held in place by bolts 7. In the chamberintervening between the proximate faces of impeller hub 2a andstationary end member 6 is the entire sealing system of the instantinvention, the same incorporating as a part thereof a float ing sealingunit of the type illustrated in US. Patent 3,028,163. Sealing unit 8 issupported by and rides with a running fit on pump shaft 5. Seen as inFIGURE 1 of the drawings forming part of the present application,sealing unit 8 is flanked by two generaiiy similar but not identicalsub-assemblies 9 and 10, the former being stationary and bearing againstcarbon sealing ring 8a and the latter being rotatable with impeller 2and pump shaft 5 and bearing against carbon sealing ring 812. Sealingrings Sa and form part of and rotate with sealing unit 8.

When stationary sub-assembly 9 is about to be installed in the pump, itis first provided with a snugly fitting resilient gasket 11 of annularshape: see FIGURES 1 and 2. Such gasket, which may be of leather,rubber, synthetic resin or the like, closely engages the adjoiningportions of subassembly 9; i.e., those portions that are to be clampedin place by stationary end member 6. On the opposite end of the scalingsystem, rotatable sub-assembly 10 intervenes between sealing unit 8 andimpeller hub 2a. An annular gasket 12, likewise of leather, rubber orsynthetic resin, is interposed between the portions of the sub-assemblyfarthest removed from sealing unit 8 and the shoulder 13 on shaft 5.When impeller 2 is in position, gasket 12 is compressed between shoulder13 and sub-assembly 10.

Thus both ends of the sealing system of the present invention aresupported in liquid-tight fashion within the limits of cylindricalextension 1a, the outboard end bearing against stationary end member 6and the inboard end engaging hub 2a of impeller 2.

An annular spacer of stepped configuration constitutes the outermostcomponent of stationary sub-assembly 9. Best seen in FIGURE 2, it ischaracterized by a flat, annular washer-like portion 14- extendingnormally to the longitudinal axis of the sealing system, by anintermediate shoulder 15, and by an inwardly directed flange-like lip 16of circular shape. Preferably formed from a moderately heavy sheet ofstainless steel, this spacer is substantially rigid, having only alimited amount of flexibility. Lip 16 serves to support a trapeziformannular carrier 17, likewise of stainless steel, formed after thefashion of a circular channel with an inclined bottom wall. Of the twoside walls of carrier 17, the one of greater diameter receives lip 16,which fits snugly therein. The telescoping parts are held together inliquid-tight fashion by a metallic bond of the type developed bycontinuous resistance welding.

The construction of the carrier 17 employed in subassembly 9, shown inFIGURE 2, and the construction of the carrier 17 employed insub-assembly 10, shown in FIGURE 3, are the same. Thus these componentsare interchangeable with each other. The same is true as regards thestationary seating element 18 employed in subassembly 9 of FIGURE 2 andthe rotatable seating element 18 forming part of sub-assembly it) ofFIGURE 3.

The precise manner in which carriers 17 support seating elements 18 andmaintain them in the desired relation to sealing unit 8 will be apparentfrom the detailed description of sub-assembly and the exploded viewmaking up FIGURE 4.

As appears from FIGURE 4, sub-assembly 10 is comprised, rotatable apartfrom gasket 12, of carrier 17, seating element 18, a stepped spacer 19of annular shape, and an annular retainer 20, of which the two lastmentioned components will be described first. Notwithstanding the factthat stepped spacer 19 and retainer 20 appear as separate elements inFIGURE 4, in practise they form a unitary structure, being spot weldedtogether in the relationship shown in FIGURE 3. In this structure,retainer 20 serves several purposes: (a) it acts to stiffen spacer 19;(b) it locates it in the desired relation to reduced portion 4 of shaft5, this mainly by virtue of the presence of circular flange 20a; and (c)it helps retain gasket 12 in position.

The portion of spacer 19 appearing at the extreme right in FIGURE 4comprises a fiat, annular washer-like portion with a central opening 25aof slightly greater diameter than the diameter of the reduced portion 4of shaft 5. The shoulder 26 imparting the stepped appearance to spacer19 intervenes between washer-like portion 25 and a flange-like lip 27 ofcircular configuration on the opposite side of spacer 19. From FIGURE 3it will be noted that lip 27 is received within carrier 17. Beingpreferably formed from moderately heavy stainless steel sheet, theseparts can advantageously be welded together by continuous resistancewelding to provide a liquid-tight joint. The resulting structure islargely rigid but not without a moderate amount of flexibility, moreparticularly in carrier 17.

Bottom wall 28 of carrier 17 is inclined at an angle of approximately 45to the longitudinal axis of the sealing system. The two side walls areso constructed that side wall 29 makes an obtuse angle and side wall 30makes an acute angle with bottom wall 28. Preferably, side wall 29parallels the longitudinal axis of the sealing system while side wall 30deviates from parallelism therewith by a very small angle, normallyabout 3 and less in any event than about 7 /2". Forming side wall 30 inthis way makes it possible to attach seating element 18 to carrier 17 inparticularly tenacious fashion. By providing them with complementarysurfaces, the two can be made to adhere so tenaciously as to require theuse of a tool to separate them.

From FIGURE 4 it may be observed that holding face 31 has a tapercomplementing the taper of side wall 30 of carrier 17; that is to say,the angle by which holding face 31 departs from parallelism with thelongitudinal axis of the sealing system is a matter of only a fewdegrees, usually about 3 and not more as a rule than about 7 /2 Ifdesired, some other method of attaching carrier 17 to seating element 18may be used, but the method described above and illustrated in FIGURES lto 4 of the drawings is a particularly satisfactory one, more especiallyfor the reason that it admits, when necessary, of limited relativemovement as between carrier 17 and seating element 18 in a directionparalleling the longitudinal axis of the sealing system.

As appears from FIGURES 3 and 4, seating element 18 is provided with acircumferential flange 32 extending beyond holding face 31 in a radialdirection. On the side thereof away from stepped spacer 19, seatingelement 18 has a highly finished sealing face 33, preferably one thathas been machined and lapped with an accuracy within a few light bands.By virtue of flange 32, sealing face 33 of seating element 18 can berelatively broad, permitting of the development of considerable relativemovement in a transverse direction between seating element 18 and theadjacent sealing ring (8a or 811) forming part of sealing unit 8: seeFIGURE 1. It will be noted that in relation to the other components ofthe sub-assemblies of which they form part, seating elements 18 are ofmassive size.

In many cases, seating elements 18 can to excellent advantage be ofstainless steel. In the drawings, they are cross hatched to indicatethat they are of metal. They may, however, be of any other suitablematerial, including ceramic materials, comminuted compressed carbon,hard rubber, nylon polytetrafluoroethylene (Teflon) and the like.Although FIGURE 1 shows sealing rings 8a and 8b as stippled to indicatethat they are of comminuted compressed carbon, they may, if desired, beof ceramic material, hard rubber, nylon, Teflon, or any other suitablesubstance. Normally, sealing rings 8a and 8b on one hand and seatingelements 18 on the other should not be of the same material.

FIGURE 5 shows a seating element 35 of Teflon in which a stainless steelstay ring has been incorporated. Holding face 36, circumferential flange37 and sealing face 38 closely resemble the analogous portions ofseating element 18 (FIGURE 4). However, seating element 35 is provided,on the side of the seating element away from sealing face 38, with anannular recess 39 for stay ring 40. The latter acts to stabilize seatingelement 35 against creep under load such as is so often encountered withcomponents of Teflon, whether filled or unfilled.

By constructing sub-assemblies 9 and 10 in the manner described above,each develops a fairly high degree of rigidity. Within the sealingsystem as a whole, there can nevertheless be a good deal ofyieldability, both lengthwise and transversely, more especially withinsealing unit 8. As a result, endwise movement of shaft 5 and evenlateral movement of the shaft in a direction transverse to its own axiscan be tolerated within comparatively wide limits, up to and above .050"in each case. Where there is such movement, sealing unit 8 tends tocenter itself in relation to the shaft, which is particularlyadvantageous.

In installing sub-assemblies 9 and 10, it is difiieult and in factvirtually impossible for the installer to distort the seating elements.The latter result is one that sometimes comes about when seatingelements of kinds commonly used in conventional sealing systems aredrawn up too tightly by the mechanic by whom the installation is beingmade. Distortion of the seating element, if it occurs, tends to keep thesealing unit from operating at maximum efliciency. In sealing systemsincorporating the present invention, this is not a problem.

It is intended that the patent shall cover, by summarization in appendedclaims, all features of patentable novelty residing in the invention.

What is claimed is:

1. In a machine having a housing, a shaft extending through an openingin the housing, and first and second end members encompassing the shaftin spaced relation to each other, the combination of a sealing unitfloating on the shaft and, between said sealing unit and said first andsecond end members, two generally similar sub-assemblies each of whichcomprises (a) an annular seating element in sealing engagement with thesealing unit, (b) a moderately flexible carrier formed after the fashionof a circular channel, said carrier supporting the seating element insuch sealing engagement, and (c) a substantially rigid spacer supportingthe carrier in telescopic fashion and extending in a generally axialdirection from the carrier to the adjacent end member.

2. In a machine heaving a housing, a shaft extending through an openingin one of the walls of the housing, a rotatable end member mounted onthe shaft, and a stationary end member spaced from the rotatable endmember, the combination of a shaft-supported sealing unit of thefloating type and, in the space between the rotatable end member and theproximate face of the sealing unit, a subassembly comprising (a) agenerally annular seating element in sealing engagement with theproximate face of the sealing unit, (b) a moderately flexiblechannel-shaped annulus engaging and serving as a carrier for saidseating element, and (c) a substantially rigid spacer of generallyannular shape supporting said channel-shaped annulus and extendingthence into engagement with the rotatable end member wherein the spaceris rigidly coupled to the rotatable end member.

3. In a machine having a housing, a shaft extending through an openingin one of the walls of the housing, a rotatable end member mounted onthe shaft, and a stationary end member spaced from the rotatable endmemher, the combination of a shaft-supported sealing unit of thefloating type and, in the space between the rotatable end member and theproximate face of the sealing unit, a sub-assembly comprising (a) agenerally annular seating element in sealing engagement with theproximate face of the sealing unit, (b) a moderately flexiblechannel-shaped annulus engaging and serving as a carrier for saidseating element, and (c) a substantially rigid spacer of generallyannular shape supporting said channel-shaped annulus and extendingthence into engagement with the rotatable end member wherein the spaceris clamped between the rotatable end member and a shoulder on the shaft.

References Cited UNITED STATES PATENTS 3,079,605 2/1963 Thomas et al27727 3,028,163 4/1962 Heinrich 27763 1,820,100 8/1931 Thompson 277861,759,029 5/1930 \Vishart 27765 3,104,884 9/1963 Kerlin 277-235 X3,058,718 10/1962 Johnson 277235 2,646,001 7/1953 Ray 27761 LAVERNE D.GEIGER, Primary Examiner. I. S. MEDNICK, Assistant Examiner.

1. IN A MACHINE HAVING A HOUSING, A SHAFT EXTENDING THROUGH AN OPENINGIN THE HOUSING, AND FIRST AND SECOND END MEMBERS ENCOMPASSING THE SHAFTIN SPACED RELATION TO EACH OTHER, THE COMBINATION OF A SEALING UNITFLOATING ON THE SHAFT AND, BETWEEN SAID SEALING UNIT AND SAID FIRST ANDSECOND END MEMBERS, TWO GENERALLY SIMILAR SUB-ASSEMBLIES EACH OF WHICHCOMPRISES (A) AN ANNULAR SEATING ELEMENT IN SEALING ENGAGEMENT WITH THESEALING UNIT, (B) A MODERATELY FLEXIBLE CARRIER FORMED AFTER THE FASHIONOF A CIRCULAR CHANNEL, SAID CARRIER SUPPORTING THE SEATING ELEMENT INSUCH SEALING ENGAGEMENT, AND (C) A SUBSTANTIALLY RIGID SPACER SUPPORTINGTHE CARRIER IN TELESCOPIC FASHION AND EXTENDING IN A GENERALLY AXIALDIRECTION FROM THE CARRIER TO THE ADJACENT END MEMBER.